Saponification of alkaline-earth cyanids.



UNITED STATES PATENT orrron.

KARL BOSCH, OF LUDWIGSHAFEN:ON-THE-RHINE, GERMANY, ASSIGNOR TO BAD ISCHEANILIN & SODA FABRIK, OF LUDWIGSHAFEN-ON-THE-RHINE,rGERMANY, A CORPO-RATION.

SAPONIFICATION OF ALKALINE-EARTH CYANIDS.

Specification ofLetters Patent.

Patented Feb. 2, 1909.

Application filed January 4, 1907. 'SeriaINo. 350,844.

. philosophy and chemist, subject of the King of Prussia, residing atLudwigshaienori-the-Rhine,Germany, have invented new I and usefulImprovements in the Saponification of Alkaline-Earth Cyanide, of whichthe following'is a specification.

The usual method hitherto employed of obtaining ammonia from cyanids ofthe alkaline earths has consisted in saponifying the said cyanids byheating them with steam at temperatures bet 769D 300 and 500 C. (see"for instance Dingler Pol gt. J 011m., 1860, p.

316; Mond, German Patent No. 21,175, p. 2; Alder, German Patent No.12351, p. 5).- The ammonia obtained according to this process, however,contains considerable" quantities of gases which are produced asbyproducts, such for instance as carbon monoxid and hydrogen, moreoverwhena fairly pure cyanid containing only small quantities of free oxidisemployed, a considerable quantity of hydrocyanic acid does not becomesaponified, but, combined with the ammonia which has beenproduced,distils over in the form of ammonium oyanid. Consequently this' processis open to the objections that impure ammonia is obtained and a part ofthe nitrogen is not converted, into ammonia. If the reaction be carriedout at lower temperaturps,

althou h the formation of carbon rnononid and of ydrogen may be avoided,yet a part of the hydrocyanic acid remains unsaponified and distils overwit-lithe ammonia, which is thus obtained in impure condition. I

have now discovered'that the saponification of the cyanids of thealkaline earths can be carried out so that the whole of the nitrogencontained in the said cyanide is converted into ammonia byheating theraw oyanidwith water, or steam, at temperatures not exceeding 250 0.,provided that the heating be carried out underfiiressure. The ammonia isthus obtained in'the pure condition. In carrying out my invention, thetime and the 'nia is almost theoretical.

temperature employed can be varied within certain limits and the processbe carried out at a lower temperature for a longer time, or at a highertemperature for ashorter time.

The following is an example of how my invention may bacarried out, butmy invention is not confined to this example. The parts are by weight.Reduce four hundred (400) parts of barium cyanid to a coarse powder andintroduce it into six hundred (600) parts of water in a steam-jacketedautoclave provided with a stirring apparatus; While stirring, raise thetemperature, slowly, to one'ln ndred and fifty (150) degrees centigradeand maintain this temperature for about five (5) hours until thepressure in the autoclave remains constant, thus showing that thesaponification is complete. On opening the autoclave the ammonia, whichis saturated with aqueous vapor, but is other: wise pure, streams outand can be freed from water by cooling and, if necessary, by passingthrough quicklime, and can then be compressed, or treated, or employed,in any other desired manner. The yield of ammo- The residue re mainingin the autoclave can be worked up in any desired manner and yieldsformic acid, also in almost theoretical amount.

Now what I claim is:

1. The process of saponifying cyanide of the alkaline earths whichconsists in heating such cyanids with water under pressure at atemperature not exceeding two hundred and fifty degrees centigrade.

2. The process of saponifying barium cyanid by heating it with waterunder ressure at a temperature not exceeding two undred and fiftydegrees centigrade.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

' KARL BOSCH.

Witnesses:

ERNEST F. EHRHARDT, J. Auto. LLOYD.

